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From:   Andreas Gruenbacher <agruenba@redhat.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@infradead.org>,
        "Darrick J. Wong" <djwong@kernel.org>,
        Paul Mackerras <paulus@ozlabs.org>, Jan Kara <jack@suse.cz>,
        Matthew Wilcox <willy@infradead.org>, cluster-devel@redhat.com,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        ocfs2-devel@oss.oracle.com, kvm-ppc@vger.kernel.org,
        linux-btrfs@vger.kernel.org,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH v8 12/17] iomap: Fix iomap_dio_rw return value for user copies
Date:   Tue, 19 Oct 2021 15:41:59 +0200
Message-Id: <20211019134204.3382645-13-agruenba@redhat.com>
In-Reply-To: <20211019134204.3382645-1-agruenba@redhat.com>
References: <20211019134204.3382645-1-agruenba@redhat.com>
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When a user copy fails in one of the helpers of iomap_dio_rw, fail with
-EFAULT instead of returning 0.  This matches what iomap_dio_bio_actor
returns when it gets an -EFAULT from bio_iov_iter_get_pages.  With these
changes, iomap_dio_actor now consistently fails with -EFAULT when a user
page cannot be faulted in.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/iomap/direct-io.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 4ecd255e0511..a2a368e824c0 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -371,6 +371,8 @@ static loff_t iomap_dio_hole_iter(const struct iomap_iter *iter,
 	loff_t length = iov_iter_zero(iomap_length(iter), dio->submit.iter);
 
 	dio->size += length;
+	if (!length)
+		return -EFAULT;
 	return length;
 }
 
@@ -402,6 +404,8 @@ static loff_t iomap_dio_inline_iter(const struct iomap_iter *iomi,
 		copied = copy_to_iter(inline_data, length, iter);
 	}
 	dio->size += copied;
+	if (!copied)
+		return -EFAULT;
 	return copied;
 }
 
-- 
2.26.3